The Research Of Charging Pile Based On Rectification Technology And LLC Resonance Technology

Recently,the environmental problems are more serious,the development of electric vehicle industry is encouraged by the government to ease the problems of environmental pollution and crisis of gasoline energy.The development of electric vehicle industry is inseparable from the construction of its infrastructure especially the construction of charging pile.Therefore,the research on charging pile with high power factor,anti-jamming capability and high efficiency is very significant for electric vehicle industry.The two circuits AC-DC and DC-DC are designed to constitute the two stages structure of the system.AC-DC employs the topology of PWM rectifier with three-phase voltage,and PI control and auto-disturbance rejection control(ADRC)combine with a controller to improve the anti-jamming capability and the power factor.The half-bridge LLC resonant converter is employed as the topology of the post-stage circuit.The steady-state model and the circuit parameters are designed by the fundamental analysis,such that the system can have a high efficiency when the circuit output satisfies the requirement.The topology of the front-stage circuit and post-stage circuit is detailed analysis in this paper.The PI dual-closed loop control for the PWM rectifier with three-phase voltage in the front-stage circuit is designed,but the anti-jamming capability of the method is weak.Therefore,the ADRC technology with strong anti-jamming capability is employed to design a new controller.The controller is combined with PI control and ADRC and is built a simulation model based on the platform of Matlab/Simulink.The new controller has a stronger anti-jamming capability by comparing the simulation waveforms when the load has a mutation or grid voltage has a disturbance.The working principle of post-stage circuit LLC resonant converter in each frequency band is analyzed in the paper.The steady-state model,voltage gain and the characteristics of input impedance are analyzed by the fundamental analysis,and the resonator parameters are designed.Simultaneously,the parameter limits of ZVS conditions for the LLC resonant converter MOS transistor are also analyzed,and according to the design specifications,the circuit parameters are designed.The circuit is verified with the simulation result which is built by the PSIM platform.Finally,the low power prototype of LLC circuit is produced to verify the feasibility of the method and the correction of the parameters design.The ZVS can turn on or off through the LLC resonant transformer MOS transistor according to the waveforms which is measured by the prototype.The system can reduce the losses and improve the efficiency.The reasons that system efficiency is change in different measurement conditions are analyzed.